Tyrannosaurus Rex Skulls and What’s Your Poison?

by Jason King on September 7, 2014

Tyrannosaurus Rex SkullWell, I have so much to write about this week that I might have to split this blog post into two. Maybe I just need to do a little less 3D printing and a little more writing and publishing.

Anyway, last week I wrote about the largest thing I’ve ever 3D printed, a Celtic Skull.

Well, not only did I print another one this week in MakerBots natural (clear crystal like) PLA, but I printed a Tyrannosaurus Rex Skull which was even bigger and far more impressive.

I printed two bottle openers, one in PLA and another in colorFabbs new XT Copolyester, so I can do a strength test. That should be fun, seeing how many beer bottles I can open with each before they break.

I’ve tested colorFabbs bronzeFill filament to see if it conducts electricity. If it did I was going to use it for copper or zinc plating, but it didn’t conduct at all so that concludes that experiment.

Oh yeah and I 3D printed a little Shamrock Shot Glass which goes nicely with the bottle openers. Are you spotting a pattern yet?

That’s enough of the summary, now it’s time for a few details and some pictures.

Crystal Celtic Skull

Celtic Skull with Rafts and SupportsAfter the success of the Celtic Skull I printed in green last week (just because I had lots of green filament spare) I thought it’d be cool to print one in clear PLA.

With Halloween looming it should look pretty good in the window if I illuminate it with a torch or a few LEDs.

As you can see from the pictures it looked like it was made from ice while it was still on the build plate, with the rafts and supports still in place.

The only issue I had with it was the same issue I had with the green version, my filament was in a knot on the reel again and kept tightening throughout the print.

3D Printed Illuminated SkullI thought I’d fixed this but I hadn’t so again it required some supervision while printing to ensure it didn’t tighten too much and prevent extrusion.

I have since checked and untangled all of my spools and I now always thread the end of the filament though the hole in the spool to prevent further tangles.

Hopefully this is the last I’ll see of this problem and I’ll be able to leave my 3D printer alone to print unsupervised. Another lesson learned I think.

Although my photography still needs a little work I did manage a picture of the skull in the dark with a torch behind it, just to demonstrate the reason I printed it in the first place. I hope you like it.

Tyrannosaurus Rex Skull

Now, I’m not obsessed by skulls or anything but I was now ready to print something even bigger and a common theme on Thingiverse seems to be variants (or remixes as they call them) of the Tyrannosaurus Rex Skull.

It seemed like the natural choice for me so I downloaded a four part T-Rex Skull and set to work. The four parts that all fit together are as follows:

  • Main Skull
  • Jaw Bone
  • Rod (for the stand)
  • Base (for the stand)

Although I printed the rod and base for the stand I don’t like them much so I’ve omitted them from the main picture at the top of this post. The main skull and jaw bone clip together nicely though to make the complete skull.

3D Printed T Rex Skull MountedThe print went really well, but I only printed it in low res (0.3 mm layer height) and I used purple PLA. Again, just because I have lots of it. I would have preferred to do it in white so I might buy some and try a high resolution version in white PLA.

There’s also a great looking finish which I’ve seen but have no idea to do yet. You print in white, rub something dark (paint or similar) all over the print then clean it off.

The pits, holes and indents all stay dark but the raised areas are clean white. I’ve seen this done on various prints but am yet to learn exactly how it’s done.

From memory the jaw took around 1.5 hours to print and the main skull took around 5.5 hours. The rod took a matter of minutes and I can’t remember how long the base took because I had a few attempts. It required a few attempts because it is large, flat and rectangular. This is one of the worst shapes for warping and it did Warp up from the Build Plate a few times until I used a raft to prevent this.

The T-Rex Skull is definitely the most eye catching thing I’ve printed so far and if you have a 3D printer I can highly recommend it if you want to create a little show piece to demonstrate what your 3D printer can do.

What’s Your Poison?

I mentioned a wile ago that I’d ordered both of colorFabbs Filament Sample Packs. These consist of lots of colors and some special filaments containing wood, bronze and glow in the dark plastic.

XT Copolymer Bottle OpenerThe only one I’d not tested up to this point was one called XT Copolyester. This stuff is clear, FDA approved (so it’s safe to be in contact with food) and supposedly much stronger than PLA.

Well, a quick bend and break test with the raw filament does prove it’s stronger than PLA and much less brittle, but I needed a more fun test. So, I printed out two bottle openers, one in PLA and one in XT.

Obviously the PLA one was easy to print, that’s one of the main characteristics of PLA. The XT one however required a temperature of 250 degrees which is quite hot. I believe my Replicator 2 can handle this temperature without issues but some printers might start to struggle at such temperatures.

It did warp a little, which PLA wouldn’t do with such a small item. That aside when it had printed some of the outer layers came loose because it didn’t look like it had fused together too well.

Shamrock Shot GlassHaving never printed in XT before I reserve judgement because it is indeed much stronger than PLA. I think with the right settings (temperature, rafts etc) it has great potential where strength is a requirement. I’ll continue to tweak the settings and report back my findings.

As for the Shamrock Shot Glass, I don’t know what inspired me to print this but I saw it on Thingiverse and thought it would be a good little print. Lets be honest I have plenty of green filament so it was a good excuse to use up a little more.

Someone did ask me if PLA was safe to drink from. Well, it’s not FDA approved like XT Copolyester is but I’m sure that the drink you put in it is far more toxic than the PLA itself. I thought that was a fair answer.

I think that’s enough info for you to absorb for now. Thanks for reading and I’ll be writing again soon about some other exciting stuff I’ve been up to in the 3D printing world (there is much more). I’ve already added a video to my YouTube Channel if you want a sneak preview. A quick clue is “YHT” and if you follow me on Twitter you may already know.

Happy 3D printing and as ever feel free to Like, ShareComment and download your FREE eBook: Beginners Guide to 3D Printing at Home.

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